Questions 12-14 are related to the following: Let x be a normally distributed ra
ID: 3070779 • Letter: Q
Question
Questions 12-14 are related to the following: Let x be a normally distributed random variable with a mean of 110 and a standard deviation of 8. 12 What is the probability that x will be above 128? a 0.0372 b 0.0808 c 0.0122 d 0.0588 13 What is the probability that x will be between 100 and 120? a 0.6284 b 0.7888 c 0.5229 d 0.8945 14 What middle interval includes 95% of x-values? P(x < x < x) = 0.95 a 123.84 135.73 b 82.77 131.62 c 94.30 125.70 d 111.25 128.75 Questions 12-14 are related to the following: Let x be a normally distributed random variable with a mean of 110 and a standard deviation of 8. 12 What is the probability that x will be above 128? a 0.0372 b 0.0808 c 0.0122 d 0.0588 13 What is the probability that x will be between 100 and 120? a 0.6284 b 0.7888 c 0.5229 d 0.8945 14 What middle interval includes 95% of x-values? P(x < x < x) = 0.95 a 123.84 135.73 b 82.77 131.62 c 94.30 125.70 d 111.25 128.75Explanation / Answer
12. P(X > 128)
= P(z > (128 - 110)/8)
= P(z > 2.25)
= 0.0122
Option C is correct.
13. P(100 < X < 120)
= P(-1.25 < z < 1.25)
= 0.7888
Option B is correct.
14. x1 = 110 - 1.96*8 = 94.3
x2 = 110 + 1.96*8 = 125.7
Option C is correct.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.